1. Field of the Invention
The present disclosure relates to an inverter, and particularly, to a multi-level medium-voltage inverter using a unit power cell.
2. Background of the Invention
A multi-level medium-voltage inverter is an inverter in which an effective value of an input line-to-line voltage has input power of 600V or higher, and an output phase voltage thereof has multiple stages (or multiple levels). A medium-voltage inverter is generally used to drive a motor having large capacity ranging from hundreds of kW to tens of MW, and mainly used in the fields such as fans, pumps, compressors, traction, hoist, conveyor, and the like.
A general voltage-type medium-voltage inverter uses a cascaded H-bridge inverter or a cascaded neutral point clamped (NPC) inverter as a modified inverter of the cascaded H-bridge inverter. The cascaded NPC inverters have emerged with its small volume, relative to existing cascaded H-bridge inverters.
Multi-level medium-voltage inverters applied to various fields are required to include smaller elements and have higher efficiency.